A typical ball 10 appears in FIG. 1. A typical ball has various characteristics. The ball has a particular weight, diameter, density, and dimple pattern. Striking a dimpled ball tends to create an improved flight path over striking a ball with no surface irregularities.
Golf balls are subject to two sets of rules. The first is the rules of the organization under whose rules the game is to be played. In many cases, that is the United States Golf Association (USGA). The USGA sets forth the limitations on golf balls to ensure that balls conform to certain standards to permit fairness among golfers. The USGA also certifies balls as meeting their rules.
There are a variety of rules a ball must follow under the USGA. For instance, the USGA has established rules regarding maximum weight, minimum size, and spherical symmetry. The maximum ball weight is 1.62 oz (45.93 g) and the minimum diameter is 1.68 inches (42.672) in diameter. The ball must be designed to be spherically symmetrical. These rules are updated every year, but the basic rules tend to remain the same.
The ball is also limited by the basic rules of physics. For example, balls fly differently based on the number, pattern, shape, and size of the dimples on the ball. Because many of the other variable features of the ball are regulated by the USGA, modifying the dimple patterns is a strategy used to improve the flight performance of the ball.
Modification of the size, number, and depth of the dimples can change the performance of a ball. On average, deep dimples on a ball tend to increase lift. Shallow dimples also allow the ball to have a higher trajectory and often create a longer flight time. Deep dimples allow the ball to have a lower trajectory an often create a longer run distance. This tends to create greater control, particularly in poor weather conditions. Increasing the number of dimples tends to create a straighter flight for the ball, but there is not a great deal of variation among balls that have between 300 and 500 dimples.
In addition to modifying the size and depth of the dimples, a ball will often have dimples that are arranged into a particular pattern. Common dimple patterns are the icosahedral and the dodecahedral. The icosahedral pattern is based on a polyhedron with twenty identical triangular faces, much like a twenty-sided die. Similarly, a dodecahedral is based on a polyhedron with twelve identical faces in the shape of pentagons. In addition, FIG. 2 shows a ball 20 that includes a dodecahedral pattern of multiple pentagons 22 on the surface of the ball 20. In addition to these patterns, other balls use other patterns that include multiple faces of varying polygonal and round shapes. Some balls include a pattern of dimples in a single shape and other balls include a pattern of dimples in a plurality of shapes.
Due to many factors, such as the limitations of the USGA rules and the materials from which balls are made, the ability to modify dimple size too greatly is limited. It is desirable that new and nonobvious structures that modify dimple size be developed.